For example, the CropSyst model considers heat-stress effects on harvest index for several crops, including wheat, sunflower, and peanut ( Challinor et al., 2005 Moriondo et al., 2011), Stratonovitch and Semenov (2015) included the effects of heat stress on both grain number and grain size in the Sirius2010 wheat model, and detailed routines for the stress effect have been suggested for heat-stress that affects spikelet sterility in rice ( Nguyen et al., 2014 van Oort et al., 2014).įor this current study, we collected detailed observations of biomass growth, grain yield, and yield components for two winter wheat cultivars over 4 years of phytotron experiments that contained different levels and durations of heat stress at the critical growth stages of anthesis and grain filling. For example, heat stress occurring at anthesis causes sterile florets and reduced grain numbers ( Farooq et al., 2011 Prasad and Djanaguiraman, 2014), while the final grain size can be affected by stress during the early grain growth stages ( Hawker and Jenner, 1993 Farooq et al., 2011).Īlgorithms have been suggested to quantify the effects of heat stress on the determination of grain yield. High temperature also directly affects grain set and grain size, and these impacts need to be considered in models. For example, the phenology simulations of the WheatGrow model have been improved by including the impact of heat stress on the duration of grain filling via its acceleration of senescence, but grain yields are still over-estimated ( Liu et al., 2016 a). Whilst most early studies focused on the effects of increasing average temperatures on yield, more recently attempts have been made to include the impact of extreme temperatures on crop growth and the determination of yield. Temperature is one of the most important climatic factors for crop growth and the determination of grain yield ( Porter and Gawith, 1999), and its impacts on production have been quantified with crop models in numerous studies (e.g. Growth simulation models have been widely used for assessing climate impacts on crop production ( White et al., 2011 a).
![wheat biomass sensitivity analysis apsim wheat biomass sensitivity analysis apsim](https://ars.els-cdn.com/content/image/1-s2.0-S1161030101001162-gr3.gif)
Grain number, grain weight, heat stress, model improvement, source–sink relationship, WheatGrow Introduction These improvements to the crop model will be of significant importance for assessing the effects on crop production of projected increases in heat-stress events under future climate scenarios. Sensitivity analysis showed that the improved model was able to reproduce the responses to various observed heat-stress treatments. When tested with data obtained under field conditions, the improved model showed a good ability to reproduce the decreasing dynamics of grain yield and its components with increasing post-anthesis temperatures. Compared to the original model, the improved version decreased the simulation errors for grain yield, grain number, and grain weight by 73%, 48%, and 49%, respectively, in an evaluation using independent data under heat stress in the phytotron conditions. The integration of our process-based stress routines into the original WheatGrow model significantly enhanced the predictions of the biomass dynamics of the stems and spikes, the grain yield, and the yield components under heat stress.
![wheat biomass sensitivity analysis apsim wheat biomass sensitivity analysis apsim](https://i1.rgstatic.net/publication/344229115_Performance_Comparison_of_the_APSIM_and_CERES-Wheat_models_in_Guanzhong_Plain_China/links/5f5e57a692851c078964e372/largepreview.png)
Biomass partitioning to stems and spikes was modified under heat stress based on a source–sink relationship.
![wheat biomass sensitivity analysis apsim wheat biomass sensitivity analysis apsim](https://slideplayer.com/slide/4891378/16/images/13/Using+APSIM+to+test+another+model+(OVERSEER®).jpg)
These relationships included reduced grain set under stress at anthesis and decreased potential grain weight under stress during early grain filling. We observed negative impacts of heat stress on biomass partitioning and grain growth in environment-controlled phytotron experiments over 4 years, and we quantified relationships between the stress and grain number and potential grain weight at anthesis and during grain filling using process-based heat stress routines. Grain yield of wheat and its components are very sensitive to heat stress at the critical growth stages of anthesis and grain filling.